ok. I have it narrowed down to the Redline oil, but which Redline product? Below is a description of each. I figure that either the 75W/140NS or the Heavy Shockproof would work. But again, which would be better for both the transmission and rear end? I am no oil "expert".
75W140NS
A heavier product what works well over a wide range of loads and temperatures, This GL-5-type gear oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting. Can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.
Heavy ShockProof
A unique lubricant containing a suspension of solid microscopic particles as an extreme pressure agent--unique solid dispersion which cushions gear teeth to help prevent tooth breakage and allows the use of lower viscosities. Recommended for heavily-loaded racing differentials and transmissions, Off Road racing and problem gearboxes. The viscosity characteristics allow the lubricant to resist throwoff and provide a film thickness similar to a 75W250 grade, while providing the same low fluid friction as an SAE 75W90.